The development of mobile communications technologies has resulted in continuous emergence of related new technologies. A Wideband Code Division Multiple Access (WCDMA) system is a 3rd generation wireless communications system that is most widely used currently. How to develop the WCDMA system so as to meet a requirement of a user for high-speed uplink and downlink data transmission is most important research work in the wireless communications field. From the fifth release (R5), a series of important technologies, such as high speed downlink packet access (HSDPA) and high speed uplink packet access (HSUPA), are introduced into WCDMA so as to increase uplink and downlink data transmission rates. After research of several releases, increasing transmission efficiency of a radio channel has reached a bottleneck.
In total transmit power of a base station of the WCDMA system, pilot occupies a relatively large portion. Functions of the pilot include determining cell coverage, channel estimation, and so on, where main functions of the channel estimation further include demodulating a shared channel (that is, phase reference), demodulating a control channel, demodulating a data channel, and measuring channel quality. In a single-antenna mode, the foregoing functions of the pilot are all implemented by a primary pilot that is continuously sent on a primary common pilot channel (P-CPICH), where transmit power of the primary pilot is determined by a network, and generally occupies 10% of the total transmit power of the base station. In a dual-antenna mode, the functions are jointly implemented by the primary pilot that is sent on the P-CPICH and a secondary pilot that is sent on a secondary common pilot channel (S-CPICH), where the primary pilot sent on the P-CPICH and the secondary pilot sent on the S-CPICH jointly implement functions of demodulating a data channel and measuring channel quality, and the primary pilot sent on the P-CPICH implements functions of determining cell coverage, demodulating a shared channel, and demodulating a control channel. The primary pilot and the secondary pilot are both sent continuously on their own pilot channel, and transmit power of the primary pilot and the secondary pilot is determined by the network. Generally, the primary pilot on the P-CPICH occupies 10% of the total transmit power of the base station, transmit power of the secondary pilot on the S-CPICH has a fixed deviation D (which is generally 3 dB) compared with the transmit power of the primary pilot on the P-CPICH, and the transmit power of the primary pilot and the secondary pilot occupies 15% of the total transmit power of the base station. The primary pilot on the P-CPICH and the secondary pilot on the S-CPICH are both transmitted directly without performing beamforming (Beam-forming).
For a user equipment (UE) end, after a user equipment receives a pilot signal, a feedback channel quality indicator (CQI) is provided based on measurement of the pilot signal. However, to save transmit power of a base station, after a special pilot that is specially used to implement demodulating a data channel is introduced into a side of the base station, the UE still feeds back a CQI to the base station according to measurement of the primary pilot but not based on measurement of the special pilot; that is, in the prior art, there is no mechanism of feeding back a CQI based on the special pilot that is introduced into the base station, and therefore, current channel quality cannot be reflected objectively and accurately.